Technical Field
An aspect of the disclosure relates to a sheet conveyer device.
Related Art
A device having an ultrasonic sensor to detect multiple feeding of sheets is known. The multiple feed detectable ultrasonic sensor may be used in, for example, a sheet conveyer. For example, signals indicating ultrasonic waves, which are transmitted through sheets and received in the sensor, may be amplified, and an integral of the amplified signals may be compared with a threshold value to detect multiple feeding of the sheets.
The sheet conveyer may be equipped with an amplifier unit and a determination unit for determining multiple feed of sheets, and with another amplifier unit and another determination unit for determining presence or absence of a sheet in a predetermined position of the sheet conveyer. The sheet conveyer may amplify signals indicating received ultrasonic waves by an amplification rate prepared for the multiple feed determination and compare an integral of the amplified signals with a threshold value prepared for multiple feed determination to determine multiple feeding of sheets. The sheet conveyer may further amplify the signals indicating the received ultrasonic waves by an amplification rate prepared for the sheet-presence determination and compare an integral of the amplified signals with a threshold value prepared for a sheet presence-determination to determine presence or absence of the sheet.